**2. Materials and Methods**

The VIT-2 vacuum plasma unit (IDTI RAS—MSTU STANKIN, Moscow, Russia) [34,36] was used to deposit coatings with the filtered cathodic vacuum arc deposition (FCVAD) technology [34–41]. The VIT-2 unit contained two arc evaporators with a pulsed magnetic field and one arc evaporator with filtering of the vapor-ion flow. Moreover, the complex contains a source of pulsed bias voltage

supply to a substrate, a dynamic gas mixing system for reaction gases, systems for automatic chamber pressure control and for process temperature control, and a system for the stepless adjustment of planetary gear rotation.

The VIT-2 unit has three cathode systems, in which cathodes of Al 99.1 at.%, Ti 99.9 at.% and also of Cr-Mo (50–50 at.%) are installed. Cylindrical cathodes with the diameter of 80 mm were used. Three cathodes of Ti-Al (80–20 at.%) were used to deposit the (Ti,Al)N commercial coating.

Coating deposition rate is 100 nm per minute.

The parameters for the process of coating deposition are presented in Table 1.


**Table 1.** Parameters of stages of the technological process of the deposition of coatings.

Note: *ITi* = current of titanium cathode, *ITi-Al* = current of Ti-Al cathode, *IAl* = current of aluminum cathode, *ICr-Mo* = current of Cr-Mo cathode, *pN* = gas pressure in chamber, *U* = voltage on substrate.

The nanoindentation technique and an Instron Wilson Hardness Group Tukon tester at the load of 0.01 N were used to determine the coating microhardness.

During the turning of workpieces made of AISI 1045 steel, a CU 500 MRD lathe (ZMM Sliven, Sliven, Bulgaria) with a ZMM CU500 MRD variable-speed drive (ZMM Bulgaria, Sofia, Bulgaria) was applied. No coolants or lubricants were used during the process of cutting. SNUN ISO 1832:2012 carbide inserts played a role of substrates, with the parameters as follows: γ = –7◦, α = 7◦, λ = 0, r = 0.4 mm; cutting mode: *f* = 0.25 rpm, *ap* = 1.0 mm, and *vc* = 300 m/min. Four experiments were conducted for each coating, and the obtained values of flank wear were processed to get the polynomial functions exhibited on the curve. The limit wear criterion was assumed as flank wear rate *VBmax* = 0.4 mm. Five tests of cutting properties were carried out, after which the information was statistically processed. Average values were determined for five experiments, these average values were used to plot the graph. Polynomial dependencies were obtained, on the basis of which graphs of the dependence of the flank wear on the cutting time were plotted.
